Đáp án:
$a) A=|x|+1$
$TH1: x≥0$
$=> A=x+1$
$TH2: x<0$
$=> A=-x+1$
$b) B=|x+2|+2$
Vì: $x≥-2$
$=> x+2≥0$
$=> B=x+2+2=x+4$
$c) |x+1|+2x$
Với $x<-1=> x+1<0$
Hay $-x-1+2x$
$=>x-1$
$d) D=5x-2|x+1|$
$TH1: x+1≥0$
$=> 5x-2(x+1)=5x-2x-2=3x-2$
$TH2: x+1<0$
$=> 5x-2(-x-1)=5x+2x+2=7x+2$
BẠN THAM KHẢO NHA!!!